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telephotographic — adj. of or pertaining to telephotography, of or pertaining to the photography of distant objects using a telephoto lens of electronic image enhancing equipment … English contemporary dictionary

telephotographic — adj. of or for or using telephotography. Derivatives: telephotographically adv … Useful english dictionary

telephotographic lens — Telephoto lens Tel e*pho to lens n. a special compound camera lens with a long effective focal length but used in a camera with a short focal length, allowing large images to be obtained of distant objects when used in a camera in place of an… … The Collaborative International Dictionary of English

Telephoto lens — Tel e*pho to lens n. a special compound camera lens with a long effective focal length but used in a camera with a short focal length, allowing large images to be obtained of distant objects when used in a camera in place of an ordinary lens;… … The Collaborative International Dictionary of English

F-number — In optics, the f number (sometimes called focal ratio, f ratio, or relative aperture [Smith, Warren Modern Lens Design 2005 McGraw Hill] ) of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; … Wikipedia